US3689033A

US3689033A - Magnetic stirrer device

Info

Publication number: US3689033A
Application number: US62478A
Authority: US
Inventors: Ola Ragnar Holmstrom; Kurt Ake Lundin
Original assignee: LKB Produkter AB
Current assignee: Pfizer Health AB
Priority date: 1970-08-10
Filing date: 1970-08-10
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: DE2136472A1; DE2136472C3; DE2136472B2; GB1334032A

Abstract

A magnetic stirrer device comprising a transversally magnetized rod disposed in a mixing chamber and means for generating an alternating transversal magnetic field within the chamber so as to obtain a rotation of the rod and a stirring of the fluids in the chamber.

Description

United States Patent Holmstrom et al.

- 1 Sept. 5, 1972 [54] MAGNETIC STIRRER DEVICE Sweden [73] Assignee: LKB-Produkter AB, Bromma,

Sweden [22] Filed: Aug. 10, 1970 [21] Appl. No.: 62,478

[52] US. Cl. ..259/5, 259/DIG. 46 [51] Int. Cl. ..B0lf 13/08 [58] Field of Search ..259/DlG. 46, 1 R, 5, 7, 9,

[56] References Cited UNlTED STATES PATENTS 3,219,318 11/1965 Hershler ..259/DIG. 46

3,167,669 l/l965 Bodine ..259/1 R X 2,999,673 9/1961 Kessler ..259/DIG. 46

FOREIGN PATENTS OR APPLICATIONS 991,941 6/1951 France ..259/DlG. 46

Primary Examiner-Walter A. Scheel Assistant ExaminerPhilip R. Coe Attorney-Christen and Sabol ABS'I RACT A magnetic stirrer device comprising a transversally magnetized rod disposed in a mixing chamber and means for generating an alternating transversal magnetic field within the chamber so as to obtain a rotation of the rod and a stirring of the fluids in the chamber.

6 Claims, 5 Drawing Figures MAGNETIC STIRRER DEVICE The invention relates to a magnetic stirrer device and more particularly to a stirrer device in which no motor is required for attaining a rotation of the magnetic stirrer.

Present day magnetic stirrer devices usually comprise a longitudinally magnetized rod, arranged in a mixing vessel. Under the vessel a similar magnet is arranged, this magnet being secured to the shaft of a motor so as to make it possible to rotate this magnet. This rotation then implies a corresponding rotation of the stirrer within the vessel. The advantages of such a magnetic stirrer in comparison with conventional mechanical stirrers is that no shafts have to be introduced into the mixing vessel and furthermore it is easy to change mixing vessels and appertaining stirrers without any time consuming cleaning procedure. The substantial drawbacks of the present day magnetic stirrers are that it is difficult to make the stirrer rotate if the volume of the vessel and consequently the stirrer is small and furthermore they can not be used for mixing streaming fluids when the axis of the stirrer has to be coaxial with the flow.

One object of this invention is to provide a magnetic stirrer device in which it is possible to use a very small mixing vessel.

Another object of the present invention is to provide a magnetic stirrer device in which the axis of the stirrer is coaxial with the stream of fluids to be mixed.

Another object of the invention is to provide a magnetic stirrer device which does not require a motor for rotating the stirrer.

The foregoing objects of the, invention will be apparent from the following detailed description when taken in conjunction with the drawing in which a preferred embodiment of the device according to the invention is shown and in which FIG. 1 is a cross sectional view of the device and FIG. 2 is an elevational view of part of the device of FIG. 1.

FIG. 3 is a top view of FIG. 2.

FIGS. 4 and 5 are elevational views of part of different embodiments of the device of this invention.

In the drawing ref. 1 denotes a cylindrical mixing chamber. The mixing chamber is provided with a magnetic stirrer 2 consisting of a transversally magnetized rod. The mixing chamber is secured between two

pole pieces

5 and 6 by means of two ribbons 3 and 4, the ribbons for instance consisting of conventional O-rings. The pole pieces are attached to a magnetic core 7 provided with two coils 8 and 9 connected to an altemating voltage source 10, the source preferably consisting of an oscillator the frequency of which can be varied. By means of the alternating voltage source and the coils an alternating magnetic field is provided within the mixing chamber 1. This alternating magnetic field will imply a rotation of the stirrer 2 and by giving the stirrer a suitable shape a mixing will be obtained within the chamber. In order to obtain a good-mixing effect the stirrer is preferably provided with vanes 11 which could either be part of the magnetic rod or be formed by a cover of the rod. This cover could for instance consist of a thin layer of tetrafluor ethylene (Teflon) which is welded at the ends of the rod in such a way that a vane isobhaind at each end of the rod. A top view of rod 2 is s own in FIG. 3 which illustrates vanes mounted on the ends of rod 2. One end of the chamber is then connected to a supplying hose 12 and the opposite end is connected to a discharging hose 13. The supplying hose is for instance connected to a junction 14 to which the different fluids to be mixed are supplied either simultaneously or alternatively.

Although only one embodiment of the invention has been described in detail above it should be understood that various changes can be carried out without departing from the spirit or scope of the invention. Thus the number of pole pieces spaced around the chamber might of course be increased as well as the number of differentially magnetized segments of the stirrer. Furthermore different shapes of the rod or the layer with which it is covered are possible. Thus a pumping effect could be obtained e.g. by having a screw shaped outer surface of the rod or by providing the rod with a bore. In FIG. 4 magnetic stirrer 15 consists of transversally magnetized rod 16 and screw shaped outer surface 17. In FIG. 17 magnetic stirrer 18 consists of transversally magnetized rod 19 and bore 20.

What is claimed is:

1. Magnetic stirrer device for stirring a liquid flow, said device comprising a tubular mixing chamber which is coaxial with said flow, a feed means for supplying the components of said flow to one end of said tubular mixing chamber, a discharge means for discharging said flow from the other end of said tubular mixing chamber, a magnetic stirrer located in said tubular mixing chamber and formed by a transversally magnetized rod which is coaxial with said chamber, and means outside of said chamber for generating an alternating magnetic field in said chamber so as to rotate said magnetic stirrer around an axis parallel to the longitudinal axis of said tubular mixing chamber.

2. The device of claim 1 wherein said alternating magnetic field generating means comprises an oscillator connected to coils on a magnetic core, the pole pieces of said core being spaced around said chamber, and said oscillator having an adjustable frequency, and wherein only one transversally magnetized rod is used.

3. The device of claim 1 wherein said transversally magnetized rod is provided on each end with a protrusion.

4. The device of claim 3 wherein said protrusions on each end of said transversally magnetized rod are vanes.

5. The device of claim 1 wherein the transversally magnetized rod has a screw shaped outer surface.

6. The device of claim 1 wherein the transversally magnetized rod is a bored rod.